Fluid solids contacting device

ABSTRACT

A fluid solids contacting device comprising a vessel; a first grid assembly section which comprises a plurality of horizontal chords spaced horizontally apart from each other and a plurality of grid platforms inserted between the horizontal chords; wherein each horizontal chord comprises a structural member with sufficient mechanical strength to withstand fluidized forces in the vessel; a plurality of chairs attached to an inside surface of the vessel and spaced circumferentially apart to support the structural member; and wherein each structural member is supported on one or more of the plurality of chairs is provided.

FIELD OF INVENTION

The instant invention relates to a fluid solids contacting device.

BACKGROUND OF THE INVENTION

In fluid bed systems operating a low superficial velocity, gas voidagessuch as bubbles tend to form which decreases contacting between the gasand the solid phase. In certain situations, internals such as chevrons,subway grating, structured packing or the like are used to break thebubbles and/or prevent formation of bubbles so as to decrease oreliminate the negative impact of inadequate solid/gas phase contact.

In a typical propane dehydrogenation process, internals are desired inthe catalyst conditioning zone, the combustor, the reactor stripper, andthe reactor itself Subway grating is an excellent choice as it breakslarge bubbles into small bubbles while not restricting radial motion inthe bed.

At a given gas velocity and flux through a given internal that blockssome of the vessel open area, the bed will flood which will not allowsolids to backmix to lower levels and will result in excessiveentrainment to the top level of the internal structure. Therefore, theopen area and associated gas velocities must be controlled within strictlimits of 0.1 ft/s-10 ft/s. Based on the solids flux and volumetric gasflow rate, the minimum open area can be calculated as to avoid flooding.Further, the spacing of internals such as subway grating must be set toavoid the streaming of gas up one side of the structure. Finally, due tothe large forces and metal movements arising from high temperatures, aunique mechanical design must be used to account for such movementwithout causing excessive stress on the vessel or the internals.

SUMMARY OF THE INVENTION

In one embodiment, the instant invention provides fluid solidscontacting device comprising a vessel; a first grid assembly sectionwhich comprises a plurality of horizontal chords spaced horizontallyapart from each other and a plurality of grid platforms inserted betweenthe horizontal chords; wherein each horizontal chord comprises astructural member with sufficient mechanical strength to withstandfluidized forces in the vessel; a plurality of chairs attached to aninside surface of the vessel and spaced circumferentially apart tosupport the structural member; and wherein each structural member issupported on one or more of the plurality of chairs.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustrating the invention, there is shown in thedrawings a form that is exemplary; it being understood, however, thatthis invention is not limited to the precise arrangements andinstrumentalities shown.

FIG. 1 is a cut-away longitudinal schematic of a first embodiment of afluid solids contacting device;

FIG. 2 is a perspective schematic view of a first embodiment of a gridassembly section of a fluid solids contacting device;

FIG. 3 is a perspective close up schematic view of a second embodimentof a grid assembly section of a fluid solids contacting device; and

FIG. 4 is a schematic illustrating a first embodiment of the chairs usedin the inventive device.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a first embodiment of the fluid solids contactingdevice is illustrated. The device includes a shell, or vessel, 10 whichencloses one or more grid assembly sections 20. Each grid assemblysection 20 is formed from a plurality of horizontal chords 30 spacedhorizontally apart from each other and a plurality of grid platforms 40(as shown in FIG. 2) inserted between the horizontal chords. Eachhorizontal chord 30 comprises a structural member with sufficientmechanical strength to withstand fluidized forces in the vessel 10.

As shown in FIGS. 2 and 3, the horizontal chords 30 have a structuralmember with a substantially I-beam or inverted T-beam shape. The shapeof the structural member is configured so that the grid platforms 40 mayrest upon a part of the structural member. As shown in FIG. 3, thestructural member comprises a bottom plate 32, a center plate 34extending upwardly from a centerline of the bottom plate 32 and cappedby a top plate 36 and wherein the grid platforms 40 may be supported onthe bottom plates 32 and/or the top plates 36. While FIG. 3 illustratesa particular form for the horizontal chords 30, it will be understoodthat the horizontal chord may have any shape with the proviso that itsupports or holds the grid platforms 40. For example, the horizontalchords 30 could be made of a flat structural member with sufficientstrength to withstand fluidized forces in the vessel 10. As furthershown in FIG. 3, the center plate 34 may optionally include openings 35into which pegs 38 may be inserted such that the pegs 38 extend over thegrid platforms 40 to prevent their upward movement. The opening and pegmethod is solely illustrative of a particular embodiment. Any method maybe used to prevent lifting of the grid platforms 40. For example, clips,ties or similar fasteners may be used. Alternatively, structuralcomponents of the horizontal chords 30, such as overhanging lips, may beused to prevent upward lifting of the grid platform 40. The disclosurefurther provides the device 10 according to any embodiment disclosedherein except that the horizontal chord 30 further comprises an end cap(not shown) on one or both ends of the chord 30. The end caps may beconfigured to improve holding of the horizontal chord 30 on or withinthe chair against fluidized forces in the vessel and/or thermal orpressure induced expansion and/or contraction. The horizontal distancebetween the horizontal chords 30 are generally dependent on size andintended use of the vessel and strength of the horizontal chords. Suchhorizontal distance is determined, in a particular embodiment, bydetermining a distance a grid platform 40 can span and hold up to a 2psi surge force.

Each grid assembly section further comprises a plurality of gridplatforms 40. Each grid platform 40 spanning two horizontal chords 30 orbetween an outermost chord and a chair may comprises one or moresections. Grid platforms 40 may fill wholly or partially the spacesbetween the horizontal chords 30. The grid platforms may optionally beshaped to allow passage of other internal members of the vessel 10. Forexample, in FIG. 2, an opening 42 in a grid platform 40 would permitpassage of another vessel internal such as a catalyst transfer line 17.The grid platforms 40 comprise any structure which forms a flowobstruction and is capable of breaking bubbles flowing in the vessel 10.Such structures include, subway grating, chevrons, packing, round bars,pipes, flat bars, angle iron, and the like. The disclosure furtherprovides a device in accordance with any embodiment disclosed herein,except that the grid platform 40 comprises one or more of the groupconsisting of subway grating, chevrons, packing structures orcombination of two or more thereof. As shown in FIG. 2, the gridassembly structure may optionally include one or two end grid platforms44 which are held in place by the outermost horizontal chords 30 a and30 b and a chair 50. Each grid platform 40 spanning two horizontalchords 30 or between an outermost chord and a chair may comprises one ormore sections. As shown in FIG. 2, for example, a grid platform 40 maycomprise three separate but abutting sections, 40 a, 40 b, and 40 c. Inthose embodiments in which a grid platform comprises more than onesection, the sections may, but need not, be attached to each other.

As further shown in FIG. 1, the vessel 10 may contain a plurality ofgrid assembly sections 20; specifically, four grid assembly sectionsshown in FIG. 1. In a particular embodiment, the number of grid assemblysections in the vessel 10 ranges from 1 to 20. All individual values andsubranges from 1 to 20 are included and disclosed herein; for example,the number of grid assembly sections can range from a lower limit of 1,5, 10, or 15 to an upper limit of 2, 6, 8, 12, 14 or 20.

Each of the grid assembly sections are spaced vertically from eachother. The vertical spacing of the grid assembly sections may be uniformor variable throughout the vessel 10. As shown in FIG. 1, each gridassembly section are separated by substantially equal distances. Thenumber of grid assembly sections 20 and the vertical distance betweenthe grid assembly sections 20 may vary from several inches to severalfeet, depending on, inter alia, the particular use for the vessel 10,size of the vessel 10, operating pressure, physical characteristics ofthe solids being fluidized, and the superficial gas velocity in thevessel 10. The superficial gas velocity in the vessel 10 may range from0.1 to 10 ft/s. All individual values from 0.1 to 10 ft/s are includedand disclosed herein; for example, the superficial gas velocity in thevessel may range from a lower limit of 0.1, 2, 4, 6 or 8 ft/s to anupper limit of 0.5, 1, 3, 5, 7, 9 or 10 ft/s. For example, thesuperficial gas velocity in the vessel may range from 0.1 to 10 ft/s, orin the alternative, from 0.1 to 7.8 ft/s, or in the alternative, 0.5 to8 ft/s, or in the alternative, from 1 to 7.7 ft/s. In a particularembodiment, the superficial gas velocity in the vessel is less than 8ft/s. As used herein, “superficial velocity” is the gas velocity in theentire vessel and the term “slot velocity” is the gas velocity throughgrid platform openings, i.e., the gas velocity not blocked by the beamsand solid parts of the grid platform. The slot velocity of the gasshould range from 1 to 8 ft/s. Slot velocities higher than 8 ft/s canresult in flooding and will not allow dense catalyst beds to form in thevessel.

Internals can be used that are capable of blocking 10% to 80% of thevessel open area. In particular embodiments, the horizontal cords mayblock 20-30% of the open area while the subway grating may block 10% to40% of the remaining open area. A standard 1 inch by 4 inch grating with¼″ thick bars can block 30% of the open area.

The disclosure further provides a device in accordance with anyembodiment disclosed herein except that the vessel is used as a reactor.

The disclosure further provides a device in accordance with anyembodiment disclosed herein except that the vessel is used as acombustor.

The disclosure further provides a device in accordance with anyembodiment disclosed herein except that the vessel is used as a catalystconditioner.

The disclosure further provides a device in accordance with anyembodiment disclosed herein except that the vessel is used as a catalyststripper.

The disclosure further provides a device in accordance with anyembodiment disclosed herein the device is a reactor or a combustor andexhibits co-current upflow conditions. Co-current upflow means that theaverage gas and solids flow are flowing upward although some solids mayback mix.

The disclosure further provides a device in accordance with anyembodiment disclosed herein the device is a catalyst conditioner orcatalyst stripper and exhibits countercurrent flow conditions with thegas flowing upward and the solids flowing downward. Flowing refers tothe average velocity of a particular stream and does not precludebackmixing. The disclosure further provides the fluid solids contactingdevice according to any embodiment described herein except that thedevice is used as a dehydrogenation reactor wherein a primary feedstockinto the device is selected from the group consisting of ethane,propane, butane, n-butane, iso-butane, isobutene, n-butene,ethylbenzene, cumene, and any combination of two or more thereof.

The grid assembly sections 20 are held in place within the vessel by theuse of chairs 50 which are spaced around the interior surface 15 of thevessel 10. The chairs 50 are attached directly or indirectly to theinterior surface 15 and provide a horizontal ledge 55 onto or into whichthe ends of the horizontal chords are placed. The placement of thechairs 50 is such that the chairs 50 support or hold the horizontalchords 30. FIG. 4 illustrates one embodiment of the chairs 50. As shownin FIG. 4, a ledge 55 is attached to a plate 57. The plate 57 may bedirectly attached to the interior surface 15 of the metal vessel oralternatively, may be attached to one or more interfaces (not shown),such as a compatible metal plate, which may be directly attached to theinterior surface 15. Optionally, the chairs 50 may be wholly orpartially wrapped, encased or coated with one or more refractorymaterials (not shown). As further shown in FIG. 4, the chair furtherincludes two side rails 58 extending upward from either side of theledge 55. The side rails 58 and the ledge 55 form a channel into whichan end of a horizontal chord may sit. In one embodiment, the end of thehorizontal chord rests within the channel such that it may move withthermal expansion and contraction during operation of the vessel. In analternative embodiment, each horizontal chord 30 is bolted or otherwiseattached to a chair 50 such that the beam may move with changes intemperature and/or pressure. Referring again to FIG. 4 it can be seenthat each of the side rails 58 include optional notches to limit thermaltransmission from the ledge 55 and side rails 58 onto the plate 57.While FIG. 4 illustrates one embodiment of a chair, other structures areincluded in the scope of the invention with the proviso that each chairis capable of supporting an end of a horizontal chord 30 whilepermitting thermal expansion and contraction. For example, in analternative configuration, the end of a horizontal chord may beconfigured as a tunnel or tube which fits over a horizontal ledge of achair without rails. Alternatively, the chair could be formed from aledge, side rails and a top thereby forming a tunnel or tube into whichan end of a horizontal chord could be placed.

As previously stated, in particular embodiments, the fluid solidscontacting device may be used as a reactor, combustor, catalystconditioner or catalyst stripper. That is, the fluid solids contactingdevice may be used under a wide range of conditions.

In a particular embodiment the fluid solids contacting device is usedfor dehydrogenation of hydrocarbons, fluidized catalytic cracking ormethanol to olefins processes. In another embodiment the fluid solidscontacting device is used for dehydrogenation of lower paraffins to formtheir corresponding olefins, or of lower olefins to form theircorresponding di-olefins. In a particular embodiment the primaryfeedstock to the fluid solids contacting device is a C3, C4, and/orethylbenzene hydrocarbon feed.

When used as a dehydrogentation reactor, the contacting a hydrocarbonfeed and a catalyst feed comprising a catalyst meeting the requirementsof a Geldart A or Geldart B classification in a fluidizeddehydrogenation reactor, i.e., the fluid solids contacting device of thepresent invention, at a catalyst feed to hydrocarbon feed ratio of 5 to100 on a weight to weight basis; wherein optionally the hydrocarbon feedand the catalyst feed have been preheated to a temperature of from about400 degrees Celsius (° C.) to about 660° C.; in a dehydrogenationreactor wherein the average contact time between the hydrocarbon feedand the catalyst feed is from about 1 to about 10 seconds; and thetemperature in the dehydrogenation reactor is maintained at a reactiontemperature from about 550° C. to about 750° C.; and the pressure in thedehydrogenation reactor is maintained from about 41.4 kilopascals (kPa)to about 308.2 kPa (about 6.0 to about 44.7 pounds per square inchabsolute, psia) at the outlet of the reactor

In most embodiments of the invention, the reaction temperature isgreater than 500° C. and preferably greater than 550° C. In particularembodiments the reaction temperature is from 500° C., preferably 550°C., more preferably 570° C., to 760° C. The average contact time shouldbe sufficiently long to dehydrogenate acceptable amounts of the startinghydrocarbon feed, but not so long as to result in unacceptable amountsof by-products. While the required contact time is related to thespecific feed, catalyst(s) and reaction temperature(s), in preferredembodiments of the invention the contact time within the dehydrogenationreactor is less than 60 seconds, preferably less than 10 seconds, morepreferably less than 8 seconds, and still more preferably less than 7seconds. Contact times may therefore range from about 0.5 or about 1 toabout 10 seconds, preferably from about 0.5 or about 1 to about 8seconds, and more preferably from about 0.5 or about 1 to about 7seconds.

The average residence time of the catalyst within the reactor ispreferably less than about 500 seconds, preferably from about 5 to about240 seconds, more preferably from about 20 to about 150 seconds, andstill more preferably from about 25 to about 100 seconds. Application ofthese times tends to decrease the amount of catalyst required for theprocess, enabling reduced catalyst inventories. Such inventories, inturn, provide the advantage of reducing operating and capital costs, incomparison with some prior art processes.

At the provided catalyst residence times and average contact times inthe dehydrogenation reactor, the applied temperature of the reactionmixture, which may be supplied in major part by the hot fresh orregenerated catalyst, is desirably from about 500° C. to about 800° C.,preferably from about 550° C. to about 760° C., and still morepreferably from about 600° C. to about 760° C. Those skilled in the artwill understand that the dehydrogenation reaction of the aforementionedcompounds is inherently endothermic and that some flexibility withinthese temperature ranges may in some instances be obtained byappropriate modification of other variables according to the needs of afacility's overall process design.

Temperatures will also be affected by the type of dehydrogenationreactor used in the inventive process. A variety of types may beutilized, provided such offer fluidized contact between the startinghydrocarbon feed and the catalyst feed. Examples of suitable reactortypes may include a co-current or countercurrent fluidized reactor, ariser reactor, a downer reactor, a fast fluidized bed reactor, abubbling bed reactor, a turbulent reactor, or a combination thereof. Inone preferred embodiment, the reactor is a combination of a fastfluidized bed or turbulent reactor in its lower portion, and a riserreactor in its upper section. In another embodiment a fast fluidized orturbulent reactor may be connected to a separate riser reactor via afrustum. The reactor may be, in certain embodiments, a hot wall reactoror a cold wall reactor, and in either case it may be refractory-lined.It may be manufactured of conventional materials used in fluid catalyticcracking (FCC) or petrochemical processing, such as, for example,stainless steel or carbon steel, and is desirably of a quality capableof withstanding the processing variables including temperature, pressureand flow rates. In particular embodiments, wherein the reactor is afluidized reactor having co-current rising flow, the highest temperaturein the dehydrogenation reactor will be found at its lower end and, asreaction proceeds and the catalyst and reaction mixture ascends, thetemperature will decrease in a gradient toward the upper end of thereactor. See, for example, U.S. Pat. No. 8,669,406 (B2) the disclosureof which is incorporated herein by reference in its entirety. Thedimensions of the reactor are generally dependent upon the processdesign of the applicable facility, and such will generally take intoaccount the proposed capacity or throughput thereof, the weight hourlyspace velocity (WHSV), temperature, pressure, catalyst efficiency, andunit ratios of feed converted to products at a desired selectivity.

In more particular embodiments the reactor may comprise two definablesections, such that the lower section may operate in a manner that is orapproaches isothermal, such as in a fast fluidized or turbulent upflowreactor, while the upper section may operate in more of a plug flowmanner, such as in a riser reactor. For example, in the previouslydescribed particular embodiment, the dehydrogenation reactor maycomprise a lower section operating as a fast fluidized or turbulent bedand the upper section operating as a riser reactor, with the result thatthe average catalyst and gas flow moves concurrently upward. As the termis used herein, “average” refers to the net flow, i.e., the total upwardflow minus the retrograde or reverse flow, as is typical of the behaviorof fluidized particles in general.

The applicable operating pressure of the dehydrogenation reactor isbroad, enabling optimization based, in embodiments wherein the inventiveprocess is applied in a retrofitted plant, upon applicable economics asallowed for by any existing equipment that will be used for theretrofit. This will be well within the general understanding of theskilled practitioner. In general the pressure may range from 6.0 to 44.7pounds per square inch absolute (psia, about 41.4 kilopascals, kPa, to308.2 kPa), but it is preferred for most embodiments including C3 and C4dehydrogenation that a narrower selected range, from 15 to 35 psia,(about 103.4 kPa to about 241.3 kPa), be employed, more preferably from15 to 30 psia (about 103.4 kPa to about 206.8 kPa), still morepreferably from 17 to 28 psia (about 117.2 kPa to about 193.1 kPa), andmost preferably from 19 to 25 psia (about 131.0 kPa to about 172.4 kPa).

The WHSV for the dehydrogenation process may conveniently range fromabout 0.1 pound (lb) to about 100 lb of hydrocarbon feed per hour (h)per lb of catalyst in the reactor (lb feed/h/lb catalyst). For example,where a reactor comprises a lower portion that operates as a fastfluidized or turbulent reactor and an upper portion that operates as ariser reactor, the superficial gas velocity may range therein from about2 feet per second (ft/s, about 0.61 meters per second, m/s) to about 80ft/s (about 24.38 m/s), preferably from about 3 ft/s (about 0.91 m/s) to10 ft/s (about 3.05 m/s), in the lower portion of the reactor, and from30 ft/s (about 9.14 m/s) to about 70 ft/s (about 21.31 m/s) in the upperportion of the reactor. In alternative but less preferred embodiments, areactor configuration that is fully of a riser type may operate at asingle high superficial gas velocity, for example, in some embodimentsat least 30 ft/s (about 9.15 m/s) throughout.

In the dehydrogenation reactor the catalyst feed to hydrocarbon feedratio ranges from about 2 to about 100 on a weight to weight (w/w)basis. In a particular embodiment for dehydrogenation of propane, theratio ranges from about 5 to about 40; more preferably from about 10 toabout 36; and most preferably from about 12 to about 24.

It is noted that, in embodiments such as in the two-part reactordescribed hereinabove, the catalyst flux is preferably from about 1pound per square foot-second (lb/ft²-s) (4.89 kg/m²-s) to about 20lb/ft²-s (97.7 kg/m²-s) in the lower portion of the reactor, and fromabout 10 lb/ft²-s (48.9 kg/m²-s) to about 200 lb/ft²⁻s (489 kg/m²-s) inthe upper portion of the reactor. In a downer reactor, a catalyst fluxof higher than about 200 lb/ft²-s may be employed, but is generally notpreferred. Those skilled in the art will be able to appropriately adjustcatalyst flux based upon WHSV and ratio of catalyst feed to hydrocarbonfeed.

When the fluid solids contacting device is used as a combustor, aportion of the at least partially deactivated catalyst is transferred toan embodiment of the fluid solids contacting device and the portion ofthe at least partially deactivated catalyst is heated to a temperatureof from 500° C. to 850° C. to combust the coke deposited on thecatalyst, using heat generated by the coke combustion itself andsupplemental fuel the heating resulting in a heated, further deactivatedcatalyst (in the case of dehydrogentation but not when used inconnection with fluid catalytic cracking or methanol to olefinsoperations).

For the case in which fluid solids contacting device is used as acombustor in an dehydrogenation process, the partially deactivatedcatalyst is heated to a temperature of at least 660° C. but no greaterthan 850° C., preferably from 700° C. to 770° C., and more preferablyfrom 720° C. to 750° C. Again, as for the dehydrogenation reactor, it ispreferred that the combustor, which serves as a part of the regenerationarea and wherein the coke will be combusted (i.e., oxidized with anoxygen containing gas) to form CO₂, comprise a lower section operatingas a fast fluidized, turbulent, or bubbling bed and an upper sectionoperating as a riser. This enables the combustor to operate with anaverage catalyst and gas flow moving concurrently upward. In thisconfiguration the internals are critical to break up the bubbles andpromote fuel, air and catalyst mixing. Another possible configuration,designed instead to enable an average catalyst flow downward and anaverage gas flow upward, comprises a fast fluidized, turbulent, orbubbling bed. Regardless of configuration, heat for the regenerator'scombustion comes from a combination of combustion of the deposited coke,i.e., the coke itself supplies heat as a result of the oxidationreaction, and combustion of a supplemental fuel for processes that don'tproduce enough coke to drive the reaction in the reactor. As the term isused herein, “supplemental” means fuel other than the coke itself.

The WHSV for the such process in the combustor may conveniently rangefrom about 0.1 to about 100 lb of air+fuel feed per hour (h) per lb ofcatalyst in the combustor (lb feed/h/lb catalyst). For example, where acombustor comprises a lower portion that operates as a fast fluidized orturbulent reactor and an upper portion that operates as a riser reactor,the superficial gas velocity may range therein from about 1 feet persecond (ft/s, about 0.3 meters per second, m/s) to about 80 ft/s (about24.38 m/s), preferably from about 2 ft/s (about 0.61 m/s) to 10 ft/s(about 3.05 m/s), in the lower portion of the reactor, and from 20 ft/s(about 6.09 m/s) to about 70 ft/s (about 21.31 m/s) in the upper portionof the combustor. In alternative but less preferred embodiments, acombustor configuration that is fully of a riser type may operate at asingle high superficial gas velocity, for example, in some embodimentsat least 30 ft/s (about 9.15 m/s) throughout.

It is noted that, in embodiments such as in the two-part combustordescribed hereinabove, the catalyst flux is preferably from about 1pound per square foot-second (lb/ft²-s) (4.89 kg/m²-s) to about 20lb/ft²-s (97.7 kg/m²-s) in the lower portion of the combustor, and fromabout 10 lb/ft²-s (48.9 kg/m²-s) to about 200 lb/ft²⁻s (489 kg/m²-s) inthe upper portion of the combustor. In a downer combustor, a catalystflux of higher than about 200 lb/ft²-s may be employed, but is generallynot preferred. Those skilled in the art will be able to appropriatelyadjust catalyst flux based upon WHSV and ratio of catalyst feed toair/supplemental fuel feed.

Pressure in the combustor ranges from 15 to 50 psia and more preferablyfrom 25 psia to 40 psia.

When the fluids solids contacting device is used as a catalystconditioner, the heated, further deactivated catalyst is subjected to aconditioning step which comprises maintaining the heated, furtherdeactivated catalyst at a temperature of at least 660° C. (for adehydrogenation process) or of at least 500° C. (for an FCC or methanolto olefins process) while exposing the heated, further deactivatedcatalyst to a flow of an oxygen-containing gas for a period of time

The conditioning also occurs within the regeneration area of the processand may be accomplished in a reactivation zone comprising, for example,a fast fluidized, turbulent, or bubbling bed. In a particularlypreferred embodiment, the reactivation zone configuration enables anaverage catalyst flow downward and an average gas flow upward, i.e.,flows corresponding to those of the combustor, but other configurationsare also possible. This conditioning step in an olefin dehydrogenationprocess may comprise maintaining the heated, further deactivatedcatalyst at a temperature of at least 660° C., but no more than 850° C.,preferably from 700° C. to 770° C., and more preferably from 720° C. to750° C., while exposing it to a flow of an oxygen-containing gas. Theconditioning is desirably carried out such that the catalyst has anaverage catalyst residence time in the oxygen-containing gas of morethan two minutes. Optionally, the regenerated catalyst may be stripped,using a gas that does not contain more than 0.5 mole percent (mol %)oxygen, to remove oxygen-containing gas molecules residing between thecatalyst particles and/or inside of the catalyst particles.

The superficial gas velocity in the inventive device when used as acatalyst conditioner may range between 0.05 to 4 ft/s, or in thealternative, from 0.05 to 2 ft/s, or in the alternative, from 2 to 4ft/s, or in the alternative, from 0.1 to 1 ft/s, or in the alternative,from 0.2 to 0.5 ft/s.

The catalyst flux in the inventive device when used as a catalystconditioner ranges between 0.1 to 20 lb/ft² sec, or in the alternative,from 0.1 to 10 lb/ft² sec, or in the alternative, from 10 to 20 lb/ft²sec, or in the alternative, from 0.5 to 5 lb/ft² sec.

The pressure in the inventive device when used as a catalyst conditionerranges from 15 to 50 psia, or in the alternative, from 15 to 32 psia, orin the alternative, from 33 to 50 psia, or in the alternative, from 25psia to 40 psia.

The fluid solids contacting device may also be used as a reactorstripper. In such application, the catalyst flux in the device rangesbetween 5 to 50 lb/ft² sec, or in the alternative, from 5 to 25 lb/ft²sec, or in the alternative, from 25 to 50 lb/ft² sec, or in thealternative, from 10 to 40 lb/ft² sec. The superficial gas velocity inthe reactor stripper ranges from 0.1 to 4 ft/s, or in the alternative,from 0.1 to 2 ft/s, or in the alternative, from 2 to 4 ft/s, or in thealternative, from 0.2 to 1.5 ft/s. Pressure for reactor stripper rangesfrom 6.0 to about 44.7, or in the alternative, from 6 to 25 psia, or inthe alternative, from 25 to 44.7 psia, or in the alternative, from 15psia to 35 psia. The temperature in the reactor stripper ranges from 400to 750° C., or in the alternative, from 400 to 575° C., or in thealternative, from 575 to 750° C., or in the alternative, from 450 to650° C.

The present invention may be embodied in other forms without departingfrom the spirit and the essential attributes thereof, and, accordingly,reference should be made to the appended claims, rather than to theforegoing specification, as indicating the scope of the invention.

We claim:
 1. A fluid solids contacting device comprising: a vessel; afirst grid assembly section which comprises a plurality of horizontalchords spaced horizontally apart from each other and a plurality of gridplatform(s) inserted between the horizontal chords; wherein eachhorizontal chord comprises a structural member with sufficientmechanical strength to withstand fluidized forces in the vessel and eachgrid platform is attached to one or more horizontal chords in a mannerto prevent upward movement of the grid platform; a plurality of chairsattached directly or indirectly to an inside surface of the vessel andspaced circumferentially apart to support the structural member; andwherein each structural member is supported on one or more of theplurality of chairs, and wherein the structural member comprises abottom plate, a center plate extending upwardly from a centerline of thebottom plate and capped by a top plate and wherein the grid platformsare supported on the bottom plates and/or the top plates.
 2. The fluidsolids contacting device according to claim 1, further comprising one ormore additional grid assembly section(s) spaced vertically apart fromeach other and from the first grid assembly section.
 3. The fluid solidscontacting device according to claim 1, wherein the grid platformscomprise one or more of the group consisting of subway grating,chevrons, packing structures or any structure which forms a flowobstruction and is capable of breaking bubbles.
 4. The fluid solidscontacting device according to claim 1, where a gas slot velocity isless than 8 ft/s.
 5. The fluid solids contacting device according toclaim 1, wherein the device is a reactor, a combustor, a catalystconditioner or a catalyst stripper.
 6. The fluid solids contactingdevice according to claim 5, where the reactor, combustor, catalystconditioner or catalyst stripper is used in a dehydrogenation processwherein one or more of the group consisting of ethane, propane, butane,n-butane, iso-butane, isobutene, n-butene, ethylbenzene, cumene, and anycombination of two or more thereof are used as a primary feedstock. 7.The fluid solids contacting device according to claim 6, where thedevice is a reactor or a combustor and exhibits co-current upflowconditions.
 8. The fluid solids contacting device according to claim 6,where the device is a catalyst conditioner or catalyst stripper andexhibits countercurrent flow conditions.